title: An image-based gait simulation study of tarsal kinematics in women with hallux valgus.
abstract: BACKGROUND
  Although not well understood, foot kinematics are changed with hallux valgus.
  
  
  OBJECTIVE
  The purpose of this study was to examine tarsal kinematics in women with hallux valgus deformity.
  
  
  METHODS
  A prospective, cross-sectional design was used.
  
  
  METHODS
  Twenty women with (n=10) and without (n=10) deformity participated. Data were acquired with the use of a magnetic resonance scanner. Participants were posed standing to simulate gait, with images reconstructed into virtual bone datasets. Measures taken described foot posture (hallux angle, intermetatarsal angle, arch angle). With the use of additional computer processes, the image sequence was then registered across gait conditions to compute relative tarsal position angles, first-ray angles, and helical axis parameters decomposed into X, Y, and Z components. An analysis of variance model compared kinematics between groups and across conditions. Multiple regression analysis assessed the relationship of arch angle, navicular position, and inclination of the first-ray axis.
  
  
  RESULTS
  Both the hallux and intermetatarsal angles were larger with deformity; arch angle was not different between groups. The calcaneus was everted by ≥6.6 degrees, and the first ray adducted (F=44.17) by ≥9.3 degrees across conditions with deformity. There was an interaction (F=5.06) for the first-ray axis. Follow-up comparisons detected increased inclination of the first-ray axis over middle stance compared with late stance in the group with deformity.
  
  
  CONCLUSIONS
  Gait was simulated, kinetics were not measured, and sample size was small.
  
  
  CONCLUSIONS
  There were group differences. Eversion of the calcaneus and adduction of the first ray were increased, and the first-ray axis was inclined 24 degrees over middle stance in women with deformity compared with 6 degrees in control participants. Results may identify risk factors of hallux valgus and inform nonoperative treatment (orthoses, exercise) strategies.
authors.affiliation: W.M. Glasoe, PT, PhD, ATC, Program in Physical Therapy, University of Minnesota, Mayo Mail Code 388, 420 Delaware St, Minneapolis, MN 55455 (USA).
authors.forename: Ward M
authors.initials: WM
authors.lastname: Glasoe
authors.forename: Vandana
authors.initials: V
authors.lastname: Phadke
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Pena
authors.forename: David J
authors.initials: DJ
authors.lastname: Nuckley
authors.forename: Paula M
authors.initials: PM
authors.lastname: Ludewig
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D002111:Calcaneus / Q000503:physiopathology; D016022:Case-Control Studies; D005260:Female; D005684:Gait / Q000502:physiology*; D006215:Hallux Valgus / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008682:Metatarsal Bones / Q000503:physiopathology; D008875:Middle Aged